An operon is controlled by a repressor. When the repressor binds to a small molecule, it is released from binding to DNA near the operon. The operon is never expressed if a mutation prevents the repressor from binding to the small molecule. The type of control illustrated is:
A) negative inducible.
B) negative repressible.
C) positive inducible.
D) positive repressible.
E) attenuation.

Question

Quizplus · Accepted Answer

The scenario describes a negative inducible operon, where the repressor binds to the operator to prevent transcription. When a small molecule (inducer) binds to the repressor, it causes the repressor to release from the DNA, allowing transcription. If the repressor cannot bind the inducer due to a mutation, the operon remains off, indicating negative inducible control.

An Operon Is Controlled by a Repressor